(CNN) -- Additional charges will be announced Thursday against a suspected serial stabber who was trying to board an overseas flight when he was arrested, Michigan authorities and the suspect's attorney said.

Elias Abuelazam's attorney said that he anticipates "there will be up to four new murder charges."

Defense attorney Edwar Zeineh said he expects the charges will bring to five the number of murder counts against Abuelazam. An arraignment could come Thursday, followed by a trial in about six months, the lawyer said.

Abuelazam is suspected in 14 stabbings -- five of which were fatal -- in Genesee County, Michigan, said prosecutor David Leyton. Abuelazam also is suspected in four attacks in Ohio and Virginia.

Leyton said he would announce the unspecified new charges at the Flint Police Department.

Previously, Abuelazam, 34, faced one murder count, five counts of assault with intent to commit murder and one charge of malicious destruction of property -- all related to attacks in Michigan.

Abuelazam was indicted last week by a grand jury in Toledo, Ohio, in the stabbing of a church janitor.

Zeineh said he does not believe investigators have insurmountable proof against his client.

"I still feel strongly there is reasonable doubt based on my review of the evidence so far," he said, without mentioning specifics.

Abuelazam's mother recently flew from Israel to Flint, Michigan, to see her son and has made several jailhouse visits.

"Her presence there as a mom was to empower her son," Zeineh said. "She helped him gather his thoughts and be [a] productive member of his defense team."

Abuelazam is suspected in the three-state string of attacks that began in May and ended in August.

Most of the stabbing victims were African-American. Federal officials have not provided a motive for the attacks, but Leesburg, Virginia, Police Chief Joseph Price has said he believed the attacker was targeting African-Americans.

Abuelazam is believed responsible for three attacks in Leesburg.

If convicted in Michigan, Abuelazam could face life in prison without parole. The state does not have the death penalty.

Abuelazam was arrested August 11 at Hartsfield-Jackson Atlanta International Airport. He was trying to board a flight to Israel when he was taken into custody, police said.

Authorities had Abuelazam in custody twice in a two-week stretch, both within hours of when stabbings were reported, but he was released. Police said he had not been linked to the attacks at the time.

Abuelazam was arrested August 5 after a traffic stop and July 29 for allegedly providing alcohol to a minor. He was fined $125 in July. In the traffic stop arrest, in Arlington, Virginia, police arrested Abuelazam after learning he had an outstanding warrant for assault. A knife and hammer were found in his car.

Authorities now believe both weapons were used in the string of stabbings. One of the attacks took place in Virginia hours after Abuelazam was released.